Provides a reified form of the ::/2 domain assignment predicate. This reified ::/3 is defined only to work for one variable (unlike ::/2).
For a single variable, V, the Bool will be instantiated to 0 if the current domain of V does not intersect with Domain. It will be instantiated to 1 iff the domain of V is wholly contained within Domain. Finally the Boolean will remain a domain variable in the range 0..1, if neither of the above two conditions hold.
Instantiating Bool to 1, will cause the constraint to behave exactly like ::/2. Instantiating Bool to 0 will cause Domain to be excluded from the domain of the variable.
Note that calling the reified form of :: will result in the Variable becoming a domain variable, even if Bool is uninstantiated.
Further note that, like other reified predicates, :: can be used infix in a GFD expression, e.g. B #= (X :: [1..10]) is equivalent to ::(X, [1..10], B).
[eclipse 2]: ::(X, [1..10, 12..30], 1).
X = X{[1 .. 10, 12 .. 30]}
[eclipse 2]: ::(X, [1..10, 12..30], 0).
X = X{[-1000000 .. 0, 11, 31 .. 1000000]}
[eclipse 2]: ::(X, [1..10, 12..30], B).
X = X{[-1000000 .. 1000000]}
B = B{[0, 1]}
[eclipse 2]: gfd:( B #= (X :: [1..10, 12..30])).
B = B{[0, 1]}
X = X{[-1000000 .. 1000000]}